About Shape Finder

What Shape Finder is

Shape Finder is a free online tool that turns two measurements into a bra size and explains the arithmetic behind the answer. You enter your underbust and bust, and the calculator shows your band, your cup, your sister sizes, and the US, UK, and EU equivalents. Nothing about it is a secret. The same formulas we use are written out on our Methodology page, so you can check our work or do the math yourself.

We built Shape Finder on one idea: there is no ‘correct’ body, only a correct measurement. A number on a tag is not a verdict on you. It is a starting point for finding something that fits and feels right. We try to be plain-spoken and numbers-first, and we leave the marketing language to the brands.

We sell nothing

Shape Finder does not sell bras, shapewear, measuring tape, supplements, or anything else. We have no store, no checkout, and no affiliate links steering you toward a particular product. That matters, because it means our sizing math has no reason to flatter a specific brand’s size chart. The answer the calculator gives you is the answer the formula gives, full stop.

How the site makes money

The site is supported by advertising. We show ads on our pages, and those ads pay for the hosting and the time it takes to research and maintain the content. Ads are clearly distinct from our editorial material, and they never change the result of a calculation. When you first visit, a consent banner lets you accept or reject advertising and analytics cookies. Our Privacy page explains exactly what is and is not collected; the short version is that your measurements are processed entirely in your browser and are never stored or sent anywhere.

Our sourcing standard

Every factual claim we publish is meant to be traceable to a named source. Where we cite research or clinical guidance, we name it directly so you can read it yourself. We are honest about limits: some of the studies we reference are small, and we say so rather than dressing them up as settled fact. We also try to be body-positive and limit-aware. We will tell you when something is unknown, when guidance says ‘consult a professional,’ and when a popular claim is not supported by evidence.

Our content is written and reviewed by the Shape Finder editorial team. We are not a fitting service and we do not employ named medical specialists; we are a small team that reads the available sources carefully and writes them up plainly. The relevant studies and guidelines we rely on are listed, with citations, on the Methodology page.

This is information, not medical or fitting advice

Shape Finder is informational. It is not a substitute for an in-person bra fitting, and it is not medical advice. A tape measure cannot account for breast shape, asymmetry, posture, a recent change in weight, pregnancy or nursing, or how a particular garment is cut. If you have pain, a medical question, or a fit problem the numbers cannot explain, please speak with a professional fitter or a clinician. Our job is to give you an honest, well-sourced starting point and to show our math while we do it.